The only regulatory required performance criteria are the aforementioned CARs. As far as determining a hostile enviroment, its left up to the PIC's discrection and endorsed by our SOP's. I'm being quoted far more than I intended here, simply trying to answer the question posed as vaguely as possible, but to correct an earlier statement; our SOP's also determine a OEI climb of 50 fpm at our
MOCA.